In the heating and air conditioning industry, it is common to run ducting from the source of the conditioned air to registers disposed at various positions within a structure. This allows the delivery of the conditioned air to particularly desired spaces defined within the structure. Until recently, such ducting has been constructed utilizing prefabricated or on-site fabricated sheet metal, and still is in some instances. However, it has now become more common to utilize a flexible ducting which varies in diameter from 4 inches to 22 inches and traditionally is manufactured in lengths of 25 feet. This flexible ducting is constructed of inner and outer layers of a plastic material, such as mylar, with an insulating foam or similar material sandwiched therebetween. A wire constructed of spring steel in a helical form is positioned between the layers of mylar and usually is encapsulated within the inner layer of mylar to maintain the flexible ducting in the desired cylindrical form.
During installation, the installer measures the length of flexible ducting of the desired diameter which is needed in any particular run. The available flexible ducting is then cut to the desired length and installed in place between the source of the conditioned air and the register by appropriate clamps or the like. In most cases, the distance between a source of air and a register is not exactly 25 feet or a multiple thereof. Therefore, the flexible ducting must usually be cut during installation. In the prior art, such cutting has been accomplished by utilizing a double-edged knife to sever the mylar-insulating-foam sandwich and when the spring steel wire is encountered, the knife is put aside and a pair of side-cutter pliers is utilized to cut the spring steel wire. Obviously, the utilization of two separate tools to cut the flexible ducting into the desired lengths requires more time, and often results in the cut being somewhat ragged.
Applicant is aware that there exists cutting tools of many types and in many forms. Such cutting tools take the form of shears for cutting relatively soft material and side-cutter type tools designed to cut wire or cable. Applicant is unaware if any cutting tool which includes a combination of cutting edges formed on the same blade designed specifically to cut soft material on one section thereof and a hard metal wire strand on another section thereof.